U.S. patent number 9,230,111 [Application Number 14/073,507] was granted by the patent office on 2016-01-05 for systems and methods for protecting document files from macro threats.
This patent grant is currently assigned to Symantec Corporation. The grantee listed for this patent is Symantec Corporation. Invention is credited to Sandeep Bhatkar, Fanglu Guo, Susanta Nanda.
United States Patent |
9,230,111 |
Nanda , et al. |
January 5, 2016 |
Systems and methods for protecting document files from macro
threats
Abstract
A computer-implemented method for protecting document files from
macro threats may include (1) identifying a document file that
contains an embedded macro, (2) locating an event-driven
programming language module that stores the embedded macro for the
document file, and (3) cleaning the event-driven programming
language module by removing procedures for the embedded macro
within the event-driven programming language module and retaining
variable definitions within the event-driven programming language
module. Various other methods, systems, and computer-readable media
are also disclosed.
Inventors: |
Nanda; Susanta (Los Angeles,
CA), Bhatkar; Sandeep (Sunnyvale, CA), Guo; Fanglu
(Los Angeles, CA) |
Applicant: |
Name |
City |
State |
Country |
Type |
Symantec Corporation |
Mountain View |
CA |
US |
|
|
Assignee: |
Symantec Corporation (Mountain
View, CA)
|
Family
ID: |
54939212 |
Appl.
No.: |
14/073,507 |
Filed: |
November 6, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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61839363 |
Jun 25, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G06F
21/562 (20130101); G06F 21/563 (20130101); G06F
21/50 (20130101); G06F 21/57 (20130101); H04L
63/1441 (20130101) |
Current International
Class: |
G06F
21/56 (20130101); G06F 12/14 (20060101); G06F
21/57 (20130101) |
Field of
Search: |
;726/22-24 |
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|
Primary Examiner: Edwards; Linglan
Attorney, Agent or Firm: ALG Intellectual Property, LLC
Parent Case Text
CROSS REFERENCES TO RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Application
No. 61/839,363, titled "DISARMING EXPLOITS BY RECONSTRUCTING
FILES," filed 25 Jun. 2013, the disclosure of which is
incorporated, in its entirety, by this reference. This application
also incorporates in its entirety U.S. application Ser. No.
14/025,779, titled "SYSTEMS AND METHODS FOR HEALING INFECTED
DOCUMENT FILES," which was filed 12 Sep. 2013 and also claims
priority to U.S. Provisional Application No. 61/839,363.
Claims
What is claimed is:
1. A computer-implemented method for protecting document files from
macro threats, at least a portion of the method being performed by
a computing device comprising at least one processor, the method
comprising: identifying a document file that contains an embedded
macro; locating an event-driven programming language module that
stores the embedded macro for the document file; cleaning the
event-driven programming language module by: categorizing a portion
of the event-driven programming language module as constituting a
procedure; categorizing another portion of the event-driven
programming language module as constituting a variable definition
as distinct from the procedure; selectively editing the embedded
macro within the event-driven programming language module by
performing at least one of removing and cleaning the portion of the
event-driven programming language module categorized as the
procedure while retaining, within the event-driven programming
language module, the other portion of the event-driven programming
language module categorized as the variable definition as distinct
from the procedure.
2. The method of claim 1, wherein the document file is formatted
based on a compound file binary format.
3. The method of claim 2, wherein: the document file comprises at
least one of a word processing document and a spreadsheet document;
the event-driven programming language module comprises a sub-tree
of a main compound file binary format tree.
4. The method of claim 2, wherein: the document file comprises a
presentation program document; the event-driven programming
language module is stored in an event-driven programming language
project storage record within a presentation program stream.
5. The method of claim 1, wherein the document file is formatted
based on an open extensible markup language format.
6. The method of claim 5, wherein: the event-driven programming
language module is stored in a compound file binary format file; a
relationship file identifies a relationship between the
event-driven programming language module and the compound file
binary format file.
7. The method of claim 1, wherein cleaning the event-driven
programming language module comprises identifying a directory
stream within an event-driven programming language storage of the
event-driven programming language module.
8. The method of claim 7, wherein cleaning the event-driven
programming language module comprises: decompressing the directory
stream; parsing the directory stream to locate a plurality of
module streams identified by the directory stream.
9. The method of claim 8, wherein cleaning the event-driven
programming language module comprises, for each of the plurality of
module streams: decompressing event-driven programming language
code of the module stream; modifying code lines by removing code
lines that contain procedure definitions; compressing the modified
code lines; storing the compressed modified code lines in the
module stream.
10. The method of claim 1, wherein cleaning the event-driven
programming language module comprises deleting a performance cache
shadow data structure comprising an array of bytes that forms an
implementation-specific and version-dependent performance cache for
a project containing the event-driven programming language
module.
11. A system for protecting document files from macro threats, the
system comprising: an identification module, stored in memory, that
identifies a document file that contains an embedded macro; a
location module, stored in memory, that locates an event-driven
programming language module that stores the embedded macro for the
document file; a cleaning module, stored in memory, that cleans the
event-driven programming language module by: categorizing a portion
of the event-driven programming language module as constituting a
procedure; categorizing another portion of the event-driven
programming language module as constituting a variable definition
as distinct from the procedure; selectively editing the embedded
macro within the event-driven programming language module by
performing at least one of removing and cleaning the portion of the
event-driven programming language module categorized as the
procedure while retaining, within the event-driven programming
language module, the other portion of the event-driven programming
language module categorized as the variable definition as distinct
from the procedure; at least one processor configured to execute
the identification module, the location module, and the cleaning
module.
12. The system of claim 11, wherein the document file is formatted
based on a compound file binary format.
13. The system of claim 12, wherein: the document file comprises at
least one of a word processing document and a spreadsheet document;
the event-driven programming language module comprises a sub-tree
of a main compound file binary format tree.
14. The system of claim 12, wherein: the document file comprises a
presentation program document; the event-driven programming
language module is stored in an event-driven programming language
project storage record within a presentation program stream.
15. The system of claim 11, wherein the document file is formatted
based on an open extensible markup language format.
16. The system of claim 15, wherein: the event-driven programming
language module is stored in a compound file binary format file; a
relationship file identifies a relationship between the
event-driven programming language module and the compound file
binary format file.
17. The system of claim 11, wherein the cleaning module cleans the
event-driven programming language module by identifying a directory
stream within an event-driven programming language storage of the
event-driven programming language module.
18. The system of claim 17, wherein the cleaning module cleans the
event-driven programming language module at least in part by:
decompressing the directory stream; parsing the directory stream to
locate a plurality of module streams identified by the directory
stream.
19. The system of claim 18, wherein the cleaning module cleans the
event-driven programming language module, for each of the plurality
of module streams, at least in part by: decompressing event-driven
programming language code of the module stream; modifying code
lines by removing code lines that contain procedure definitions;
compressing the modified code lines; storing the compressed
modified code lines in the module stream.
20. A non-transitory computer-readable-storage medium comprising
one or more computer-readable instructions that, when executed by
at least one processor of a computing device, cause the computing
device to: identify a document file that contains an embedded
macro; locate an event-driven programming language module that
stores the embedded macro for the document file; clean the
event-driven programming language module by: categorizing a portion
of the event-driven programming language module as constituting a
procedure; categorizing another portion of the event-driven
programming language module as constituting a variable definition
as distinct from the procedure; selectively editing the embedded
macro within the event-driven programming language module by
performing at least one of removing and cleaning the portion of the
event-driven programming language module categorized as the
procedure while retaining, within the event-driven programming
language module, the other portion of the event-driven programming
language module categorized as the variable definition as distinct
from the procedure.
Description
BACKGROUND
Email is now a ubiquitous form of communication. To transmit files
between persons and organizations, email may also include the files
as attachments. Unfortunately, email attachments may contain
payloads from attackers intending to compromise computer
security.
As one example, document files may include macros that host a
shellcode, which is a payload used in the exploitation of a
software vulnerability. Attackers may encrypt the shellcode to
prevent static scanning-based detection. When executed, the macro
may automatically decrypt the shellcode and trigger a memory error
to gain control over a document application (e.g., a word
processing or spreadsheet application). To bypass address space
layout randomization defenses, the attackers may use a heap
spraying technique that fills large parts of memory with NOP ("No
Operation") commands and shellcode. After extracting shellcode into
memory, macros can also trigger a bug that corrupts a code pointer
value. If the pointer points to the shellcode part of memory, then
the attack may succeed.
Accordingly, the instant disclosure identifies and addresses a need
for additional and improved systems and methods for protecting
document files from macro threats.
SUMMARY
As will be described in greater detail below, the instant
disclosure generally relates to systems and methods for protecting
document files from macro threats by identifying a document that
contains a macro, locating a software module that stores the macro
for the document, and cleaning the software module by removing
procedures from the software module. In one specific example, a
computer-implemented method for protecting document files from
macro threats may include (1) identifying a document file that
contains an embedded macro, (2) locating an event-driven
programming language module that stores the embedded macro for the
document file, and (3) cleaning the event-driven programming
language module by removing procedures for the embedded macro
within the event-driven programming language module and retaining
variable definitions within the event-driven programming language
module.
In one embodiment, the document file may be formatted based on a
compound file binary format. The document file may include at least
one of a word processing document and a spreadsheet document. The
event-driven programming language module may include a sub-tree of
a main compound file binary format tree.
In some embodiments, the document file may include a presentation
program document. The event-driven programming language module may
be stored in an event-driven programming language project storage
record within a presentation program stream.
In one embodiment, the document file may be formatted based on an
open extensible markup language format. The event-driven
programming language module may be stored in a compound file binary
format file. A relationship file may identify a relationship
between the event-driven programming language module and the
compound file binary format file.
In some examples, cleaning the event-driven programming language
module may include identifying a directory stream within an
event-driven programming language storage of the event-driven
programming language module. Cleaning the event-driven programming
language module may include decompressing the directory stream.
Cleaning the event-driven programming language module may also
include parsing the directory stream to locate a plurality of
module streams identified by the directory stream.
In some embodiments, cleaning the event-driven programming language
module may include, for each of the plurality of module streams:
(1) decompressing event-driven programming language code of the
module stream, (2) modifying code lines by removing code lines that
contain procedure definitions, (3) compressing the modified code
lines, and (4) storing the compressed modified code lines in the
module stream.
In some examples, cleaning the event-driven programming language
module may include deleting a performance cache shadow data
structure that includes an array of bytes that forms an
implementation-specific and version-dependent performance cache for
a project containing the event-driven programming language
module.
In one embodiment, a system for implementing the above-described
method may include (1) an identification module, stored in memory,
that identifies a document file that contains an embedded macro,
(2) a location module, stored in memory, that locates an
event-driven programming language module that stores the embedded
macro for the document file, (3) a cleaning module, stored in
memory, that cleans the event-driven programming language module by
removing procedures for the embedded macro within the event-driven
programming language module and retaining variable definitions
within the event-driven programming language module, and (4) at
least one processor configured to execute the identification
module, the location module, and the cleaning module.
In some examples, the above-described method may be encoded as
computer-readable instructions on a non-transitory
computer-readable medium. For example, a computer-readable medium
may include one or more computer-executable instructions that, when
executed by at least one processor of a computing device, may cause
the computing device to (1) identify a document file that contains
an embedded macro, (2) locate an event-driven programming language
module that stores the embedded macro for the document file, and
(3) clean the event-driven programming language module by removing
procedures for the embedded macro within the event-driven
programming language module and retaining variable definitions
within the event-driven programming language module.
Features from any of the above-mentioned embodiments may be used in
combination with one another in accordance with the general
principles described herein. These and other embodiments, features,
and advantages will be more fully understood upon reading the
following detailed description in conjunction with the accompanying
drawings and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings illustrate a number of exemplary
embodiments and are a part of the specification. Together with the
following description, these drawings demonstrate and explain
various principles of the instant disclosure.
FIG. 1 is a block diagram of an exemplary system for protecting
document files from macro threats.
FIG. 2 is a block diagram of an exemplary system for protecting
document files from macro threats.
FIG. 3 is a flow diagram of an exemplary method for protecting
document files from macro threats.
FIG. 4 is a block diagram of an exemplary document file analyzed by
a system for protecting document files from macro threats.
FIG. 5 is a block diagram of an exemplary macro analyzed by a
system for protecting document files from macro threats.
FIG. 6 is a block diagram of an exemplary computing system capable
of implementing one or more of the embodiments described and/or
illustrated herein.
FIG. 7 is a block diagram of an exemplary computing network capable
of implementing one or more of the embodiments described and/or
illustrated herein.
Throughout the drawings, identical reference characters and
descriptions indicate similar, but not necessarily identical,
elements. While the exemplary embodiments described herein are
susceptible to various modifications and alternative forms,
specific embodiments have been shown by way of example in the
drawings and will be described in detail herein. However, the
exemplary embodiments described herein are not intended to be
limited to the particular forms disclosed. Rather, the instant
disclosure covers all modifications, equivalents and alternatives
falling within the scope of the appended claims.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
The present disclosure is generally directed to systems and methods
for protecting document files from macro threats. As will be
explained in greater detail below, the systems and methods
described herein may resolve, delete, and/or render harmless
macros, including macro exploits or malware. The systems and
methods may also autonomously resolve macros in document files in a
repeated or batch manner, with little or no user intervention.
Moreover, the systems and methods may also resolve macros without
compromising other functionality of the document file, such as
ACTIVEX functionality, as discussed further below.
The following will provide, with reference to FIGS. 1-2, detailed
descriptions of exemplary systems for protecting document files
from macro threats. Detailed descriptions of corresponding
computer-implemented methods will also be provided in connection
with FIG. 3. Moreover, detailed description of a corresponding
document file will be provided in connection with FIG. 4.
Similarly, detailed descriptions of a corresponding macro will be
provided in connection with FIG. 5. In addition, detailed
descriptions of an exemplary computing system and network
architecture capable of implementing one or more of the embodiments
described herein will be provided in connection with FIGS. 6 and 7,
respectively.
FIG. 1 is a block diagram of an exemplary system 100 for protecting
document files from macro threats. As illustrated in this figure,
exemplary system 100 may include one or more modules 102 for
performing one or more tasks. For example, and as will be explained
in greater detail below, exemplary system 100 may include an
identification module 104 that may identify a document file that
contains an embedded macro. Exemplary system 100 may additionally
include a location module 106 that may locate an event-driven
programming language module that stores the embedded macro for the
document file. Exemplary system 100 may also include a cleaning
module 108 that may clean the event-driven programming language
module by removing procedures for the embedded macro within the
event-driven programming language module and retaining variable
definitions within the event-driven programming language module.
Although illustrated as separate elements, one or more of modules
102 in FIG. 1 may represent portions of a single module or
application.
In certain embodiments, one or more of modules 102 in FIG. 1 may
represent one or more software applications or programs that, when
executed by a computing device, may cause the computing device to
perform one or more tasks. For example, and as will be described in
greater detail below, one or more of modules 102 may represent
software modules stored and configured to run on one or more
computing devices, such as the devices illustrated in FIG. 2 (e.g.,
computing device 202 and/or server 206), computing system 610 in
FIG. 6, and/or portions of exemplary network architecture 700 in
FIG. 7. One or more of modules 102 in FIG. 1 may also represent all
or portions of one or more special-purpose computers configured to
perform one or more tasks.
As illustrated in FIG. 1, exemplary system 100 may also include one
or more databases, such as database 120. In one example, database
120 may be configured to store emails, email attachments, including
document files, and information about macro and other malware
threats.
Database 120 may represent portions of a single database or
computing device or a plurality of databases or computing devices.
For example, database 120 may represent a portion of server 206 in
FIG. 2, computing system 610 in FIG. 6, and/or portions of
exemplary network architecture 700 in FIG. 7. Alternatively,
database 120 in FIG. 1 may represent one or more physically
separate devices capable of being accessed by a computing device,
such as server 206 in FIG. 2, computing system 610 in FIG. 6,
and/or portions of exemplary network architecture 700 in FIG.
7.
Exemplary system 100 in FIG. 1 may be implemented in a variety of
ways. For example, all or a portion of exemplary system 100 may
represent portions of exemplary system 200 in FIG. 2. As shown in
FIG. 2, system 200 may include a computing device, such as target
computing device 202 and attacker computing device 208, in
communication with a server 206 via a network 204. Computing device
202 may be programmed with one or more of modules 102 and/or may
store all or a portion of the data in database 120. Additionally or
alternatively, server 206 may be programmed with one or more of
modules 102 and/or may store all or a portion of the data in
database 120.
In the example of FIG. 2, attacker computing device 208 may
originally create or intercept and modify an email 203. Attacker
computing device 208 may modify an attachment 205 to email 203 so
that attachment 205 includes a macro 207. Attacker computing device
208 may then transmit email 203 to target computing device 202
where a potential victim receives email. At target computing device
202, or at server 206 prior to reception at target computing device
202, one or more modules 102 may perform steps to resolve the
macro, as discussed further below. Server 206, as a mail server,
may receive email 203 through routine email transmission.
Alternatively, server 206, as a security server, may intercept
and/or monitor routine email transmissions to provide protection
from macros. Server 206 may also respond to queries from target
computing device 202, and thereby clean document files or provide
other protection on demand.
In one embodiment, one or more of modules 102 from FIG. 1 may, when
executed by at least one processor of computing device 202 and/or
server 206, enable computing device 202 and/or server 206 protect
document files from macro threats. For example, and as will be
described in greater detail below, one or more of modules 102 may
cause computing device 202 and/or server 206 to protect document
files from macro threats. For example, identification module 104
may be programmed to identify a document file, such as attachment
205 (e.g., a MICROSOFT WORD document) that contains an embedded
macro, such as macro 207. Location module 106 may be programmed to
locate an event-driven programming language module that stores
macro 207 for attachment 205. Cleaning module 108 may be programmed
to clean the event-driven programming language module by removing
procedures for macro 207 within the event-driven programming
language module and retaining variable definitions within the
event-driven programming language module.
Computing device 202 generally represents any type or form of
computing device capable of reading computer-executable
instructions. Examples of computing device 202 include, without
limitation, laptops, tablets, desktops, servers, cellular phones,
Personal Digital Assistants (PDAs), multimedia players, embedded
systems, combinations of one or more of the same, exemplary
computing system 610 in FIG. 6, or any other suitable computing
device.
Server 206 generally represents any type or form of computing
device that is capable of processing emails and/or providing
protection from macro threats. Examples of server 206 include,
without limitation, application servers and database servers
configured to provide various database services and/or run certain
software applications.
Network 204 generally represents any medium or architecture capable
of facilitating communication or data transfer. Examples of network
204 include, without limitation, an intranet, a Wide Area Network
(WAN), a Local Area Network (LAN), a Personal Area Network (PAN),
the Internet, Power Line Communications (PLC), a cellular network
(e.g., a Global System for Mobile Communications (GSM) network),
exemplary network architecture 700 in FIG. 7, or the like. Network
204 may facilitate communication or data transfer using wireless or
wired connections. In one embodiment, network 204 may facilitate
communication between computing device 202 and server 206.
FIG. 3 is a flow diagram of an exemplary computer-implemented
method 300 for protecting document files from macro threats. The
steps shown in FIG. 3 may be performed by any suitable
computer-executable code and/or computing system. In some
embodiments, the steps shown in FIG. 3 may be performed by one or
more of the components of system 100 in FIG. 1, system 200 in FIG.
2, computing system 610 in FIG. 6, and/or portions of exemplary
network architecture 700 in FIG. 7.
As illustrated in FIG. 3, at step 302 one or more of the systems
described herein may identify a document file that contains an
embedded macro. For example, at step 302 identification module 104
may, as part of computing device 202 in FIG. 2, identify a document
file as attachment 205 that contains macro 207.
As used herein, the phrase "document file" generally refers to any
file storing at least some information for presenting a page,
slide, and/or sheet to a user, typically including at least some
text. Exemplary kinds of document files include word processing
document files, spreadsheet document files, and presentation
application (e.g., POWERPOINT) document files. Moreover, as used
herein, the phrase "macro" generally refers to one or more
executable or procedure commands that may be embedded within a
document file.
Identification module 104 may identify the document file in a
variety of ways. Identification module 104 may receive a selection
of the document file (e.g., from a user). Identification module 104
may receive a request to process or clean the document file.
Similarly, identification module 104 may receive an identification
of the document file in a list or series of files to be processed
(e.g., in a batch manner). Identification module may also identify
the document file as a document file based on a name, file
extension, tag, metadata, and/or a content/body of the file.
Identification module 104 may further identify the document file
based on the behavior of other modules or applications with respect
to the file.
In one embodiment, the document file is formatted based on a
compound file binary format. As used herein, the phrase "compound
file binary (`CFB`) format" generally refers to a format of binary
file configured for storing multiple files within a single larger
file as a collection. The compound file binary format file may
correspond to a MICROSOFT OFFICE document prior to the 2007 switch
to OPEN EXTENDED MARKUP LANGUAGE ("OXML") format. In some
embodiments, the document file may include a word processing
document (e.g., MICROSOFT WORD) and/or a spreadsheet document
(e.g., MICROSOFT EXCEL). In further embodiments, the document file
may include a presentation program (e.g., MICROSOFT POWERPOINT)
document.
In one embodiment, the document file is formatted based on an open
extensible markup language format. As used herein, the phrase
"extensible markup language (`XML`) format" refers to the
standardized markup language that defines a set of rules for
encoding documents in a format that is both human-readable and
machine-readable. The phrase "open extensible markup language
format" may refer to MICROSOFT'S modified version of XML used in
the 2007 MICROSOFT OFFICE switch from the compound file binary
format, as discussed above.
At step 304 one or more of the systems described herein may locate
an event-driven programming language module that stores the
embedded macro for the document file. For example, at step 304
location module 106 may, as part of computing device 202 in FIG. 2,
locate an event-driven programming language module that stores
macro 207 for attachment 205.
As used herein, the phrase "event-driven programming language"
generally refers to a programming language in which the flow of a
program is determined by events such as sensor outputs or user
actions (e.g., mouse clicks, key presses) or messages from other
programs or threads. In a primary embodiment, one example of an
event-driven programming languages is MICROSOFT'S VISUAL BASIC FOR
APPLICATIONS ("VBA"), which may embed macros within MICROSOFT
OFFICE document files, as discussed above. Notably, a VBA module
generally refers to a collection of routines and/or data structures
that perform a specific task or implements a specific abstract data
type. VBA modules typically include two parts, a module header and
a module body. A module header may include a set of name/value
attribute pairs that specify the linguistic characteristics of the
module. A module body may include VBA source code, which may
include a set of declarations followed by procedures. VBA supports
two types of modules, procedural modules and class modules.
FIG. 4 shows an exemplary document file 402 that may be analyzed by
the systems and methods described herein. With reference to FIG. 4,
an overview follows for how location module 106 may locate the
event-driven programming language module in a variety of ways. FIG.
4 shows how macros may be stored in MICROSOFT WORD document files
in either CFB format or OXML format. In either case, the
event-driven programming language module may include macro 404,
which may correspond to a VIRTUAL BASIC FOR APPLICATIONS `storage.`
In VBA, `storages` may be analogous to directories or folders in
conventional file systems. Macro 404 may further store VBA 406,
which is another storage. As further shown in FIG. 4, document file
402 may also include dir 408, Sheet1 410, ThisWorkbook 412,
_VBA_PROJECT 414, PROJECT 416, and PROJECTwm 418, which are all
"streams." In VBA, "streams" are analogous to files in conventional
file systems.
As used herein, the phrase "event-driven programming language
module" may refer to at least a "storage" or folder, such as macro
404 in FIG. 4, and/or a "stream" or file, such as Sheet1 410 in
FIG. 4 (in the example of a spreadsheet). More generally, the
phrase "event-driven programming language module" may refer to a
logically separated unit of programming language content, such as a
separate folder, file, library, and/or section of code.
In the case of document file 402 being formatted based on CFB
format, the event-driven programming language module macro 404 may
correspond to a sub-tree of a main compound file binary format
tree. Location module 106 may locate the event-driven programming
language module in part by locating the sub-tree of the main
compound file binary format tree. Moreover, in the case of document
file 402 corresponding to a presentation program (e.g.,
POWERPOINT), the event-driven programming language module may be
stored in an event-driven programming language project storage
record within a presentation program stream. Specifically, the
event-driven programming language module may be stored within a
"VbaProjectStg" record within a "PowerPoint Document" stream.
In contrast to document file 402 being stored in CFB format, in the
case of OXML format, the event-driven programming language module
may be stored in a compound file binary format file (i.e., a CFB
file embedded within the OXML document file). A relationship file
may identify a relationship between the event-driven programming
language module and the compound file binary format file. For
example, a relationship file may include the following
relationship: <Relationship Id="rld1"
Type="http://schemas.microsoft.com/office/2006/relationships/vbaProject"
Target="vbaProject.bin"/>. Location module 106 may locate the
event-driven programming language module in part by locating the
relationship file and/or using the relationship file to locate the
binary file that stores the macro.
At step 306 one or more of the systems described herein may clean
the event-driven programming language module by removing procedures
for the embedded macro within the event-driven programming language
module and retaining variable definitions within the event-driven
programming language module. For example, at step 306 cleaning
module 108 may, as part of computing device 202 in FIG. 2, clean
the event-driven programming language module by removing procedures
for macro 207 within the event-driven programming language module
and retaining variable definitions within the event-driven
programming language module. As used herein, the phrase
"procedures" generally refers to executable code within the
event-driven programming language, as distinct from variable
declarations and definitions, which establish the name and type of
variables, and may not be included within procedures. In VBA,
variable declarations may precede procedures in module streams.
Cleaning module 108 may remove a single, or plural, procedures, and
may retain a single, or plural, variable definition, as further
discussed below.
Cleaning module 108 may clean the event-driven programming language
module in a variety of ways. In some examples, cleaning module 108
may clean the event-driven programming language module in part by
identifying a directory stream within an event-driven programming
language storage of the event-driven programming language module.
The directory stream may correspond to dir stream 408 in FIG. 4.
Dir stream 408 may constitute a special stream that contains
information about other streams within document file 402.
In some examples, cleaning module 108 may clean the event-driven
programming language module in part by decompressing the directory
stream. Moreover, cleaning module 108 may also clean the
event-driven programming language module in part by parsing the
directory stream to locate a plurality of module streams identified
by the directory stream. In the example of FIG. 4, cleaning module
108 may parse dir 408 to identify other streams, such as Sheet1 410
and PROJECT 416. In some embodiments, cleaning module 108 may clean
the event-driven programming language module in part by performing
the following for one, some, and/or each of the plurality of module
streams: (1) decompressing event-driven programming language code
of the module stream, (2) modifying code lines by removing code
lines that contain procedure definitions, (3) compressing the
modified code lines, and (4) storing the compressed modified code
lines in the module stream.
FIG. 5 shows an exemplary event-driven programming language module
502 (e.g., a decompressed VBA stream) that may be analyzed by the
systems and methods described herein. Cleaning module 108 may clean
module 502 in part by deleting procedures 506, which may be
identified in any of the ways described above, while retaining
variable declarations 504. Notably, in the example of FIG. 5,
procedures 506 correspond to an innocuous macro instead of a
malicious macro exploit. The systems and methods described herein
may remove procedures for some (e.g., one or more), all, or
substantially all macros without verifying that the macros
correspond to an exploit.
More generally, cleaning module 108 may clean the event-driven
programming language module on a line by line or section by section
basis. For each line (or section) in a plurality of lines (or
sections), cleaning module 108 may categorize the line as
corresponding to a procedure definition or as not corresponding to
a procedure definition. If the line corresponds to a procedure
definition, cleaning module 108 may remove, render blank, render
function-less, and/or comment out the line. Cleaning module 108 may
identify lines corresponding to procedure definitions as distinct
from variable declarations that do constitute (part of) a procedure
definition. Cleaning module 108 may leave variable declarations.
Moreover, cleaning module 108 may categorize lines, parts, and/or
sections of the event-driven programming language module as
constituting or corresponding to procedure and/or variable
declarations based on one or more factors. These factors may
include a procedure keyword (e.g., in VBA, these may include
"Function," "Sub," "Operator," "Get," "Set," and a matching "End"
keyword), a variable declaration keyword (e.g., in VBA, these may
include "Attribute"), and/or a relative or absolute position of the
part of the event-driven programming language module (e.g.,
variable declarations may be more likely to be located at the start
of the module, and procedure lines may be contained within other
lines marked by procedure keywords, such as "Sub" and "End").
Cleaning module 108 may similarly remove some, all, or
substantially all lines, parts, and/or sections categorized as
procedure definitions. Cleaning module 108 may perform this
cleaning for some, all, and/or substantially all streams identified
by Dir 408, and/or those streams selected or defined by a user
(e.g., upon a prompt displaying various candidate streams for
cleaning), and/or those streams designated by a security program.
Moreover, in order to preserve functionality of a document
component other than macro 207, cleaning module 108 may identify
specific variable declarations based on specific keywords such as
"ACTIVEX," "VB_Control," "Shockwave," "ShockwaveFlash,"
"ShockwaveFlash1," and/or "ShockwaveFlashObjects." In some
embodiments, cleaning module may retain those declarations while
deleting, removing, and/or rendering functionless others.
Moreover, in some examples, cleaning module 108 may clean the
event-driven programming language module in part by deleting a
performance cache shadow data structure that includes an array of
bytes that forms an implementation-specific and version-dependent
performance cache for a project containing the event-driven
programming language module. The shadow data structure may have the
specific name "PerformanceCache." Cleaning module 108 may delete
PerformanceCache from all streams within document file 402 that
contain the shadow data structure. These streams may include
_VBA_PROJECT 414, all _SRP_Streams (not shown in the example of
FIG. 4), and all other module streams.
As explained above in connection with method 300 in FIG. 3, the
systems and methods described herein may resolve, delete, and/or
render harmless macros, including macro exploits or malware. The
systems and methods may also autonomously resolve macros in
document files in a repeated or batch manner, with little or no
user intervention. Moreover, the systems and methods may also
resolve macros without compromising other functionality of the
document file, such as ACTIVEX functionality, as discussed further
above.
The above discussion of FIG. 3 provided specific details about the
systems and methods described herein. The following provides a
higher level overview of these systems and methods.
Cleaning module 108 may delete macro 207 completely by removing the
VBA storage object in OFFICE 2003 format, and by removing VBA
binary files and their corresponding relationships in OFFICE 2007
format files. However, that deletion affects the functionality of
ACTIVEX objects that store properties in VBA code. For instance,
the deletion may cause an embedded FLASH video to stop playing. The
loss of functionality (e.g., the FLASH video stopped playing) may
be particularly undesirable for security programs that enable the
selective deletion of macros. To address this problem, cleaning
module 108 may specifically refrain from deleting the event-driven
programming language module completely. Instead, cleaning module
108 may only remove procedures because the procedures could contain
exploit code. In contrast, cleaning module 108 may specifically
retain all variable definitions within the event-driven programming
language module, because the variable definitions could include
ACTIVEX property definitions.
Cleaning module 108 may perform the following specific steps to
clean the event-driven programming language module. First, cleaning
module 108 may identify the "dir" stream within the "VBA" storage
(e.g., folder). The "dir" stream is stored in compressed format.
Therefore, cleaning module 108 may decompress the "dir" stream.
Cleaning module 108 may then parse the "dir" stream to find all of
the module streams. Each entry in the "dir" stream contains
information such as the name of a stream that stores VBA code and
the offset of the VBA code within the stream.
For each of the module streams with VBA code, cleaning module 108
may modify the module stream as follows. VBA code may be stored in
a compressed form between a text offset and the end of the module
stream. Cleaning module 108 may decompress the code, remove the
code lines that contain procedure definitions, compress the code,
and finally put the modified, compressed code back in the module
stream.
Unfortunately, all the versions of MICROSOFT OFFICE applications
(e.g., WORD, XLS, PPT) loosely interpret the VBA format
specification. The applications use a version specific undocumented
shadow data structure called PerformanceCache to store metadata as
well as VBA code. The version field in the _VBA_PROJECT stream
specifies the version of VBA used to create a VBA project.
According to the specification, the version value should be 0xFFFF
on write, indicating that the main data structure be used for
interpretation. Unfortunately, the applications write a VBA
specific version in the field, causing the shadow data structure to
be used. Explicitly changing the version value to 0xFFFF does not
necessarily force the applications to use the main data structure.
Therefore, deletion of VBA procedures may not fully work, in some
cases, without the following additional step. To address
MICROSOFT'S loose interpretation of the format specification,
cleaning module 108 may explicitly delete PerformanceCache from all
the streams that include PerformanceCache, specifically
_VBA_PROJECT, all _SRP_Streams, and the module streams. With this
change, the deletion of VBA macros can be selectively applied.
FIG. 6 is a block diagram of an exemplary computing system 610
capable of implementing one or more of the embodiments described
and/or illustrated herein. For example, all or a portion of
computing system 610 may perform and/or be a means for performing,
either alone or in combination with other elements, one or more of
the steps described herein (such as one or more of the steps
illustrated in FIG. 3). All or a portion of computing system 610
may also perform and/or be a means for performing any other steps,
methods, or processes described and/or illustrated herein.
Computing system 610 broadly represents any single or
multi-processor computing device or system capable of executing
computer-readable instructions. Examples of computing system 610
include, without limitation, workstations, laptops, client-side
terminals, servers, distributed computing systems, handheld
devices, or any other computing system or device. In its most basic
configuration, computing system 610 may include at least one
processor 614 and a system memory 616.
Processor 614 generally represents any type or form of physical
processing unit (e.g., a hardware-implemented central processing
unit) capable of processing data or interpreting and executing
instructions. In certain embodiments, processor 614 may receive
instructions from a software application or module. These
instructions may cause processor 614 to perform the functions of
one or more of the exemplary embodiments described and/or
illustrated herein.
System memory 616 generally represents any type or form of volatile
or non-volatile storage device or medium capable of storing data
and/or other computer-readable instructions. Examples of system
memory 616 include, without limitation, Random Access Memory (RAM),
Read Only Memory (ROM), flash memory, or any other suitable memory
device. Although not required, in certain embodiments computing
system 610 may include both a volatile memory unit (such as, for
example, system memory 616) and a non-volatile storage device (such
as, for example, primary storage device 632, as described in detail
below). In one example, one or more of modules 102 from FIG. 1 may
be loaded into system memory 616.
In certain embodiments, exemplary computing system 610 may also
include one or more components or elements in addition to processor
614 and system memory 616. For example, as illustrated in FIG. 6,
computing system 610 may include a memory controller 618, an
Input/Output (I/O) controller 620, and a communication interface
622, each of which may be interconnected via a communication
infrastructure 612. Communication infrastructure 612 generally
represents any type or form of infrastructure capable of
facilitating communication between one or more components of a
computing device. Examples of communication infrastructure 612
include, without limitation, a communication bus (such as an
Industry Standard Architecture (ISA), Peripheral Component
Interconnect (PCI), PCI Express (PCIe), or similar bus) and a
network.
Memory controller 618 generally represents any type or form of
device capable of handling memory or data or controlling
communication between one or more components of computing system
610. For example, in certain embodiments memory controller 618 may
control communication between processor 614, system memory 616, and
I/O controller 620 via communication infrastructure 612.
I/O controller 620 generally represents any type or form of module
capable of coordinating and/or controlling the input and output
functions of a computing device. For example, in certain
embodiments I/O controller 620 may control or facilitate transfer
of data between one or more elements of computing system 610, such
as processor 614, system memory 616, communication interface 622,
display adapter 626, input interface 630, and storage interface
634.
Communication interface 622 broadly represents any type or form of
communication device or adapter capable of facilitating
communication between exemplary computing system 610 and one or
more additional devices. For example, in certain embodiments
communication interface 622 may facilitate communication between
computing system 610 and a private or public network including
additional computing systems. Examples of communication interface
622 include, without limitation, a wired network interface (such as
a network interface card), a wireless network interface (such as a
wireless network interface card), a modem, and any other suitable
interface. In at least one embodiment, communication interface 622
may provide a direct connection to a remote server via a direct
link to a network, such as the Internet. Communication interface
622 may also indirectly provide such a connection through, for
example, a local area network (such as an Ethernet network), a
personal area network, a telephone or cable network, a cellular
telephone connection, a satellite data connection, or any other
suitable connection.
In certain embodiments, communication interface 622 may also
represent a host adapter configured to facilitate communication
between computing system 610 and one or more additional network or
storage devices via an external bus or communications channel.
Examples of host adapters include, without limitation, Small
Computer System Interface (SCSI) host adapters, Universal Serial
Bus (USB) host adapters, Institute of Electrical and Electronics
Engineers (IEEE) 1394 host adapters, Advanced Technology Attachment
(ATA), Parallel ATA (PATA), Serial ATA (SATA), and External SATA
(eSATA) host adapters, Fibre Channel interface adapters, Ethernet
adapters, or the like. Communication interface 622 may also allow
computing system 610 to engage in distributed or remote computing.
For example, communication interface 622 may receive instructions
from a remote device or send instructions to a remote device for
execution.
As illustrated in FIG. 6, computing system 610 may also include at
least one display device 624 coupled to communication
infrastructure 612 via a display adapter 626. Display device 624
generally represents any type or form of device capable of visually
displaying information forwarded by display adapter 626. Similarly,
display adapter 626 generally represents any type or form of device
configured to forward graphics, text, and other data from
communication infrastructure 612 (or from a frame buffer, as known
in the art) for display on display device 624.
As illustrated in FIG. 6, exemplary computing system 610 may also
include at least one input device 628 coupled to communication
infrastructure 612 via an input interface 630. Input device 628
generally represents any type or form of input device capable of
providing input, either computer or human generated, to exemplary
computing system 610. Examples of input device 628 include, without
limitation, a keyboard, a pointing device, a speech recognition
device, or any other input device.
As illustrated in FIG. 6, exemplary computing system 610 may also
include a primary storage device 632 and a backup storage device
633 coupled to communication infrastructure 612 via a storage
interface 634. Storage devices 632 and 633 generally represent any
type or form of storage device or medium capable of storing data
and/or other computer-readable instructions. For example, storage
devices 632 and 633 may be a magnetic disk drive (e.g., a so-called
hard drive), a solid state drive, a floppy disk drive, a magnetic
tape drive, an optical disk drive, a flash drive, or the like.
Storage interface 634 generally represents any type or form of
interface or device for transferring data between storage devices
632 and 633 and other components of computing system 610. In one
example, database 120 from FIG. 1 may be stored in primary storage
device 632.
In certain embodiments, storage devices 632 and 633 may be
configured to read from and/or write to a removable storage unit
configured to store computer software, data, or other
computer-readable information. Examples of suitable removable
storage units include, without limitation, a floppy disk, a
magnetic tape, an optical disk, a flash memory device, or the like.
Storage devices 632 and 633 may also include other similar
structures or devices for allowing computer software, data, or
other computer-readable instructions to be loaded into computing
system 610. For example, storage devices 632 and 633 may be
configured to read and write software, data, or other
computer-readable information. Storage devices 632 and 633 may also
be a part of computing system 610 or may be a separate device
accessed through other interface systems.
Many other devices or subsystems may be connected to computing
system 610. Conversely, all of the components and devices
illustrated in FIG. 6 need not be present to practice the
embodiments described and/or illustrated herein. The devices and
subsystems referenced above may also be interconnected in different
ways from that shown in FIG. 6. Computing system 610 may also
employ any number of software, firmware, and/or hardware
configurations. For example, one or more of the exemplary
embodiments disclosed herein may be encoded as a computer program
(also referred to as computer software, software applications,
computer-readable instructions, or computer control logic) on a
computer-readable medium. The phrase "computer-readable medium"
generally refers to any form of device, carrier, or medium capable
of storing or carrying computer-readable instructions. Examples of
computer-readable media include, without limitation,
transmission-type media, such as carrier waves, and
non-transitory-type media, such as magnetic-storage media (e.g.,
hard disk drives, tape drives, and floppy disks), optical-storage
media (e.g., Compact Disks (CDs), Digital Video Disks (DVDs)), and
BLU-RAY disks, electronic-storage media (e.g., solid-state drives
and flash media), and other distribution systems.
The computer-readable medium containing the computer program may be
loaded into computing system 610. All or a portion of the computer
program stored on the computer-readable medium may then be stored
in system memory 616 and/or various portions of storage devices 632
and 633. When executed by processor 614, a computer program loaded
into computing system 610 may cause processor 614 to perform and/or
be a means for performing the functions of one or more of the
exemplary embodiments described and/or illustrated herein.
Additionally or alternatively, one or more of the exemplary
embodiments described and/or illustrated herein may be implemented
in firmware and/or hardware. For example, computing system 610 may
be configured as an Application Specific Integrated Circuit (ASIC)
adapted to implement one or more of the exemplary embodiments
disclosed herein.
FIG. 7 is a block diagram of an exemplary network architecture 700
in which client systems 710, 720, and 730 and servers 740 and 745
may be coupled to a network 750. As detailed above, all or a
portion of network architecture 700 may perform and/or be a means
for performing, either alone or in combination with other elements,
one or more of the steps disclosed herein (such as one or more of
the steps illustrated in FIG. 3). All or a portion of network
architecture 700 may also be used to perform and/or be a means for
performing other steps and features set forth in the instant
disclosure.
Client systems 710, 720, and 730 generally represent any type or
form of computing device or system, such as exemplary computing
system 610 in FIG. 6. Similarly, servers 740 and 745 generally
represent computing devices or systems, such as application servers
or database servers, configured to provide various database
services and/or run certain software applications. Network 750
generally represents any telecommunication or computer network
including, for example, an intranet, a WAN, a LAN, a PAN, or the
Internet. In one example, client systems 710, 720, and/or 730
and/or servers 740 and/or 745 may include all or a portion of
system 100 from FIG. 1.
As illustrated in FIG. 7, one or more storage devices 760(1)-(N)
may be directly attached to server 740. Similarly, one or more
storage devices 770(1)-(N) may be directly attached to server 745.
Storage devices 760(1)-(N) and storage devices 770(1)-(N) generally
represent any type or form of storage device or medium capable of
storing data and/or other computer-readable instructions. In
certain embodiments, storage devices 760(1)-(N) and storage devices
770(1)-(N) may represent Network-Attached Storage (NAS) devices
configured to communicate with servers 740 and 745 using various
protocols, such as Network File System (NFS), Server Message Block
(SMB), or Common Internet File System (CIFS).
Servers 740 and 745 may also be connected to a Storage Area Network
(SAN) fabric 780. SAN fabric 780 generally represents any type or
form of computer network or architecture capable of facilitating
communication between a plurality of storage devices. SAN fabric
780 may facilitate communication between servers 740 and 745 and a
plurality of storage devices 790(1)-(N) and/or an intelligent
storage array 795. SAN fabric 780 may also facilitate, via network
750 and servers 740 and 745, communication between client systems
710, 720, and 730 and storage devices 790(1)-(N) and/or intelligent
storage array 795 in such a manner that devices 790(1)-(N) and
array 795 appear as locally attached devices to client systems 710,
720, and 730. As with storage devices 760(1)-(N) and storage
devices 770(1)-(N), storage devices 790(1)-(N) and intelligent
storage array 795 generally represent any type or form of storage
device or medium capable of storing data and/or other
computer-readable instructions.
In certain embodiments, and with reference to exemplary computing
system 610 of FIG. 6, a communication interface, such as
communication interface 622 in FIG. 6, may be used to provide
connectivity between each client system 710, 720, and 730 and
network 750. Client systems 710, 720, and 730 may be able to access
information on server 740 or 745 using, for example, a web browser
or other client software. Such software may allow client systems
710, 720, and 730 to access data hosted by server 740, server 745,
storage devices 760(1)-(N), storage devices 770(1)-(N), storage
devices 790(1)-(N), or intelligent storage array 795. Although FIG.
7 depicts the use of a network (such as the Internet) for
exchanging data, the embodiments described and/or illustrated
herein are not limited to the Internet or any particular
network-based environment.
In at least one embodiment, all or a portion of one or more of the
exemplary embodiments disclosed herein may be encoded as a computer
program and loaded onto and executed by server 740, server 745,
storage devices 760(1)-(N), storage devices 770(1)-(N), storage
devices 790(1)-(N), intelligent storage array 795, or any
combination thereof. All or a portion of one or more of the
exemplary embodiments disclosed herein may also be encoded as a
computer program, stored in server 740, run by server 745, and
distributed to client systems 710, 720, and 730 over network
750.
As detailed above, computing system 610 and/or one or more
components of network architecture 700 may perform and/or be a
means for performing, either alone or in combination with other
elements, one or more steps of an exemplary method for protecting
document files from macro threats.
While the foregoing disclosure sets forth various embodiments using
specific block diagrams, flowcharts, and examples, each block
diagram component, flowchart step, operation, and/or component
described and/or illustrated herein may be implemented,
individually and/or collectively, using a wide range of hardware,
software, or firmware (or any combination thereof) configurations.
In addition, any disclosure of components contained within other
components should be considered exemplary in nature since many
other architectures can be implemented to achieve the same
functionality.
In some examples, all or a portion of exemplary system 100 in FIG.
1 may represent portions of a cloud-computing or network-based
environment. Cloud-computing environments may provide various
services and applications via the Internet. These cloud-based
services (e.g., software as a service, platform as a service,
infrastructure as a service, etc.) may be accessible through a web
browser or other remote interface. Various functions described
herein may be provided through a remote desktop environment or any
other cloud-based computing environment.
In various embodiments, all or a portion of exemplary system 100 in
FIG. 1 may facilitate multi-tenancy within a cloud-based computing
environment. In other words, the software modules described herein
may configure a computing system (e.g., a server) to facilitate
multi-tenancy for one or more of the functions described herein.
For example, one or more of the software modules described herein
may program a server to enable two or more clients (e.g.,
customers) to share an application that is running on the server. A
server programmed in this manner may share an application,
operating system, processing system, and/or storage system among
multiple customers (i.e., tenants). One or more of the modules
described herein may also partition data and/or configuration
information of a multi-tenant application for each customer such
that one customer cannot access data and/or configuration
information of another customer.
According to various embodiments, all or a portion of exemplary
system 100 in FIG. 1 may be implemented within a virtual
environment. For example, the modules and/or data described herein
may reside and/or execute within a virtual machine. As used herein,
the phrase "virtual machine" generally refers to any operating
system environment that is abstracted from computing hardware by a
virtual machine manager (e.g., a hypervisor). Additionally or
alternatively, the modules and/or data described herein may reside
and/or execute within a virtualization layer. As used herein, the
phrase "virtualization layer" generally refers to any data layer
and/or application layer that overlays and/or is abstracted from an
operating system environment. A virtualization layer may be managed
by a software virtualization solution (e.g., a file system filter)
that presents the virtualization layer as though it were part of an
underlying base operating system. For example, a software
virtualization solution may redirect calls that are initially
directed to locations within a base file system and/or registry to
locations within a virtualization layer.
In some examples, all or a portion of exemplary system 100 in FIG.
1 may represent portions of a mobile computing environment. Mobile
computing environments may be implemented by a wide range of mobile
computing devices, including mobile phones, tablet computers,
e-book readers, personal digital assistants, wearable computing
devices (e.g., computing devices with a head-mounted display,
smartwatches, etc.), and the like. In some examples, mobile
computing environments may have one or more distinct features,
including, for example, reliance on battery power, presenting only
one foreground application at any given time, remote management
features, touchscreen features, location and movement data (e.g.,
provided by Global Positioning Systems, gyroscopes, accelerometers,
etc.), restricted platforms that restrict modifications to
system-level configurations and/or that limit the ability of
third-party software to inspect the behavior of other applications,
controls to restrict the installation of applications (e.g., to
only originate from approved application stores), etc. Various
functions described herein may be provided for a mobile computing
environment and/or may interact with a mobile computing
environment.
In addition, all or a portion of exemplary system 100 in FIG. 1 may
represent portions of, interact with, consume data produced by,
and/or produce data consumed by one or more systems for information
management. As used herein, the phrase "information management" may
refer to the protection, organization, and/or storage of data.
Examples of systems for information management may include, without
limitation, storage systems, backup systems, archival systems,
replication systems, high availability systems, data search
systems, virtualization systems, and the like.
In some embodiments, all or a portion of exemplary system 100 in
FIG. 1 may represent portions of, produce data protected by, and/or
communicate with one or more systems for information security. As
used herein, the phrase "information security" may refer to the
control of access to protected data. Examples of systems for
information security may include, without limitation, systems
providing managed security services, data loss prevention systems,
identity authentication systems, access control systems, encryption
systems, policy compliance systems, intrusion detection and
prevention systems, electronic discovery systems, and the like.
According to some examples, all or a portion of exemplary system
100 in FIG. 1 may represent portions of, communicate with, and/or
receive protection from one or more systems for endpoint security.
As used herein, the phrase "endpoint security" may refer to the
protection of endpoint systems from unauthorized and/or
illegitimate use, access, and/or control. Examples of systems for
endpoint protection may include, without limitation, anti-malware
systems, user authentication systems, encryption systems, privacy
systems, spam-filtering services, and the like.
The process parameters and sequence of steps described and/or
illustrated herein are given by way of example only and can be
varied as desired. For example, while the steps illustrated and/or
described herein may be shown or discussed in a particular order,
these steps do not necessarily need to be performed in the order
illustrated or discussed. The various exemplary methods described
and/or illustrated herein may also omit one or more of the steps
described or illustrated herein or include additional steps in
addition to those disclosed.
While various embodiments have been described and/or illustrated
herein in the context of fully functional computing systems, one or
more of these exemplary embodiments may be distributed as a program
product in a variety of forms, regardless of the particular type of
computer-readable media used to actually carry out the
distribution. The embodiments disclosed herein may also be
implemented using software modules that perform certain tasks.
These software modules may include script, batch, or other
executable files that may be stored on a computer-readable storage
medium or in a computing system. In some embodiments, these
software modules may configure a computing system to perform one or
more of the exemplary embodiments disclosed herein.
In addition, one or more of the modules described herein may
transform data, physical devices, and/or representations of
physical devices from one form to another. For example, one or more
of the modules recited herein may receive a document file to be
transformed, transform the document file by cleaning the document
file of one or more macros or macro procedures, output a result of
the transformation to destination computing device or recipient
email inbox, use the result of the transformation to protect users
from macro exploits, and store the result of the transformation to
a destination computing device, mail server, and/or recipient
computer. Additionally or alternatively, one or more of the modules
recited herein may transform a processor, volatile memory,
non-volatile memory, and/or any other portion of a physical
computing device from one form to another by executing on the
computing device, storing data on the computing device, and/or
otherwise interacting with the computing device.
The preceding description has been provided to enable others
skilled in the art to best utilize various aspects of the exemplary
embodiments disclosed herein. This exemplary description is not
intended to be exhaustive or to be limited to any precise form
disclosed. Many modifications and variations are possible without
departing from the spirit and scope of the instant disclosure. The
embodiments disclosed herein should be considered in all respects
illustrative and not restrictive. Reference should be made to the
appended claims and their equivalents in determining the scope of
the instant disclosure.
Unless otherwise noted, the phrases "connected to" and "coupled to"
(and their derivatives), as used in the specification and claims,
are to be construed as permitting both direct and indirect (i.e.,
via other elements or components) connection. In addition, the
phrases "a" or "an," as used in the specification and claims, are
to be construed as meaning "at least one of." Finally, for ease of
use, the words "including" and "having," as used in the
specification and claims, are interchangeable with and have the
same meaning as the word "comprising."
* * * * *
References